“…More precisely, they proved local existence and uniqueness of weak solutions to (1), (2) under the assumption that 0 ∈ 6 (R 3 ), 1 ∈ 4 (R 3 ). Local existence and uniqueness of classical solutions to (1), (2) were also established, provided that 0 ∈ 12 (R 3 ), 1 ∈ 10 (R 3 ). Their method is to first establish local-intime well-posedness of a periodic version of (1), (2) and then construc a solution to (1), (2) as a limit of periodic solutions with divergent periods.…”